Authorities said the man -- identified by sources as Sayfullo Habibullaevic Saipov, who was an Uber and commercial truck driver living in Paterson, New Jersey -- is thought to be a "lone actor" in the attack in the Hudson River Greenway on Tuesday afternoon. U.S. counterintelligence officials added that no group has taken responsibility for the attack.

Sources said he rented the truck from a Home Depot in Passaic, drove over the George Washington Bridge and sped down the greenway for more than a dozen blocks before deliberately ramming into a school bus for children near Stuyvesant High School and P.S. 89.

Two staff members and two children on the bus were injured, police said.

The Uzbek national, who is a permanent U.S. resident, then shouted "Allahu Ackbar," got out of the rented truck and was seen running through traffic on West Street with a pellet gun and a paintball gun before being shot in the abdomen by a police officer on patrol and taken into custody. He's being treated at Bellevue Hospital.

Sources said that though Saipov lives in Paterson, he had a Florida license with a Tampa address on him when he was arrested. Police and federal agents were seen swarming the neighborhood street where he lived on Tuesday night as well as the Passaic Home Depot where he rented the flatbed truck and left his family minivan.

A family friend described the suspect as calm and hard-working, while President Donald Trump derided him as "sick and deranged."

Residents in the area said that Saipov had a wife and two young children and that they had lived in the home on and off for about three years. Fellow Muslims in the neighborhood said that while he and his wife appeared to be practicing the faith, they only saw him at the local mosque once or twice.

"We are not like him," said Mohammed Ghaith, who goes to the mosque. "Not harmful or anything like that. I don't know what he's been through or what he went through but we should all be like peace."

Kobiljon Matkarov, a Facebook friend of Saipov's, told NBC News that the two met while they were both living in Florida.

"He was very happy guy," said Matkarov, who is also from Uzbekistan. "He liked the US. He is no terrorist. He's all the time happy, smiling all the time."

Uber said Saipov had passed a background test to drive for the service, and that he had been banned from accessing the app after Tuesday's attack. The company added that it is reviewing Saipov's history with the service and cooperating with the FBI.

Saipov pleaded guilty to two traffic offenses in Pennsylvania between 2012 and 2015, according to records from the Keystone State. He was also arrested for failing to appear in court after getting another traffic citation in Missouri in 2015; he later paid a fine and served no jail time. It's not clear if he had any other criminal history beyond the traffic offenses.